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Posted: Mon Apr 30, 2012 8:16 pm
by Zeus
I think the main problem with a squeeze bore would be machining and finishing it. You could turn a taper on an annealed drill bit, then load a pine dowel with grit and polish it.

I was thinking of doing the same for a .22 ratshot gun. Just so I can charm snakes out to a longer range without going deaf if I need to do it inside.

And Fnord, I'm very upset, you made a fairly decent EFP, and used a KClO<sub>4</sub> based energetic. That's like buying a Ferrari and putting a Honda 4 cylinder in it.

Posted: Mon Apr 30, 2012 8:22 pm
by Fnord
Hey, don't complain, years ago it was all I had/could get away with :)
I have a little more chemistry knowledge now, but unfortunately no sufficiently isolated fields to apply it to.

Posted: Tue May 01, 2012 12:00 am
by HunterT
DYI wrote:
The main problem I see is that copper has a fairly high melting point...
Sarcasm doesn`t translate too well over the internet. Just to keep the record straight in case you were serious, shaped charge jets are typically well below the melting point of the metal, even in the case of copper.
Sorry about that. I didn't mean to come across as sarcastic. :oops:

I was under the impression that in shaped charge jets, the metal is liquified by the heat produced by the explosion. I should have done a little research. Sorry.

Posted: Tue May 01, 2012 3:14 am
by jackssmirkingrevenge
real chemistry aside, gave it a quick go with soda can aluminium at 5x.

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Note that the aluminium is not the burst disk, there's a separate photo paper burst disk between it and the fuel/air mix

Not too impressive, and I was immediately faced with problem for future testing - it's too bloody loud, even at low mix. I do want to try with a thicker disk though.

Posted: Tue May 01, 2012 5:16 am
by pneumaticcannons
it's too bloody loud
Y U NO BARREL?
Other than that, could using copper and higher mixes possibly solve the obvious crumpling problem? Maybe you could drip some super glue around the area where the "penetrator" meets the union to allow it to stretch out more before popping out.

Posted: Tue May 01, 2012 6:29 am
by jackssmirkingrevenge
pneumaticcannons wrote:Y U NO BARREL?
Wasn't that the point :)
Other than that, could using copper and higher mixes possibly solve the obvious crumpling problem? Maybe you could drip some super glue around the area where the "penetrator" meets the union to allow it to stretch out more before popping out.
I think a small conical "barrel" would definitely help, but not as much as higher mixes, damn urban living.

Posted: Tue May 01, 2012 6:42 am
by DYI
Gee Jack, seems like you're having an awful lot of trouble recently due to not having a containment vessel handy... :lol:

Posted: Tue May 01, 2012 7:43 am
by jackssmirkingrevenge
I have a couple of old 30 litre vacuum ovens at work that would be perfect, unfortunately they insist on continuing to work :-/

Posted: Tue May 01, 2012 9:11 am
by pneumaticcannons
Wasn't that the point
well... Oh :oops:
unfortunately they insist on continuing to work :-/
you can change that :D

Posted: Tue May 01, 2012 10:57 am
by inonickname
pneumaticcannons wrote:
it's too bloody loud
Y U NO BARREL?
Other than that, could using copper and higher mixes possibly solve the obvious crumpling problem? Maybe you could drip some super glue around the area where the "penetrator" meets the union to allow it to stretch out more before popping out.
The crumpling problem is because he has nowhere near the pressure or velocity of an actual HE.

I'm with DYI, go for a flat disk accelerator.

Posted: Tue May 01, 2012 1:27 pm
by jackssmirkingrevenge
inonickname wrote:The crumpling problem is because he has nowhere near the pressure or velocity of an actual HE.
Yup, this isn't actually going anywhere with low mixes. The taper bore seems like a more likely avenue for success for high velocity slugs.